Trim for lateral drift

[livesounder]

I'm new at this, and have been spending time spinning up and down, popping a few inches off the floor, etc., getting a feel for how this bugger behaves.

I've got the rudder and elevators trimmed to where rotational and forward/rearward drift is nominal. However, the machine continues to want to drift Left. A little when it gets light on the skids, quite a bit when it goes airborn. Attempting to apply gentle Right aileron while on the ground actually seems to make it worse, and rather than hold position, it will start to tip over. My hunch is this is due to ground affect.

So, is this Left drift something I can still trim out (as I would presume), or do I have to learn to control it real time?

Thanks

[ClayK]

Are you sure the aileron servo isn't reversed? What helicopter is this?

Leave the helicopter in a throttle hold state, stand behind it in a tail in orientation. Give right aileron input and see which way the swash plate tilts. It should tilt to the right. If it tilts left, your aileron servo is reversed. Depending on what type of swash or helicopter, will determine the correct course of action to fix it.

[livesounder]

It's a Blade CPP. Servo's are set up per the manual, although I haven't visually verified the swash plate. With enough stick, I can see the plane of the rotor blades tilting in what appears to be the correct direction. Right side moves downward with right stick (as viewed from rear).

[Pinecone]

All helis with clockwise rotor rotation will drift a bit or require a bit of right stick to hold position. They also end up leaning.

The tail rotor is pushing sideways to counter act torque. That side push will cause the drift. So you have to use right stick to keep it from drifitn, which introduces the lean.

Keep working on it. It will work. It does seem like it will tip when you frist start flying, until you learn the finesse to get it to lift off straight up.

BTW if you don't know about it, the Radd school of flight (Google it) is free and works very well.

[livesounder]

Thanks for the assist.

I've been working my way through Radd's method, which is when I found the drift issue.

After some further study and tweeking, I've got the trim adjusted to where it will remain stable as long as I Don't try to keep it on the floor and very light on the skids. I presume ground effect at work.

I would have to guess that this (at least in part) is why in all the videos I've watched of other flyers, they consistantly "jump" off the ground rather than rising slowly.

[spork]

The problem is largely that it can't be light on its skids and lean to the right at the same time. I've seen some mount their skids at a slight angle to deal with this.

[Rick Rotorhead]

livesounder.......

"I would have to guess that this (at least in part) is why in all the videos I've watched of other flyers, they consistantly "jump" off the ground rather than rising slowly. "

I think you're right. I haven't been flying helis all that long so I've been through what you are talking about, fairly recently. If you trim a heli for as stable as possible chest high hover, then try to take off the ground real slow it still drifts, mostly left, and threatens to tip over. So, a short fairly sharp jump from ground to at least knee height or higher get around this and is safer for the heli - but it takes a leap of faith (excuse pun) if you are a new flyer to suddenly leave the comfort of ground contact to the full 'in the air, can go anywhere' position in one go.

[spork]

If you want to be able to dance around lightly on the skids or training gear put a couple of washers between the skids and frame on the left side. Basically you just want to get the heli to lean to the right on the skids the same amount as it does in a hover.

[Pinecone]

The one thing I don't like about using trim, is that the trim will be wrong whem you go inverted. :)

[spork]

The one thing I don't like about using trim, is that the trim will be wrong whem you go inverted. :)

I'm not sure I follow you. If you use trim to counter a C.G. problem, it's true that it will be wrong when inverted. But if you use trim to put the swashplate where it needs to be anyway, that should be fine.

[BarracudaHockey]

I thought the tail rotor blew the other way when it was inverted? :?:

[spork]

That's true. So you'll lean a bit to the left when hovering inverted. But I don't think the swash needs to be trimmed to the right to maintain the lean to the right in a hover. Hmmmm..... I'll have to think about this.

[BarracudaHockey]

Um Rick ............ :lolol

It was a joke :D

We need an icon with a big sucker being reeled in by a fishing rod! :glasses2:

[spork]

Um Rick ............ :lolol

It was a joke :D

Yeah - but an interesting question nevertheless.